Nice quiz, but your instructions need a little more detail as to exactly what you are looking for. Uitenhage and PE for instance are part of the same municipality (as are Pretoria and Soshanguve). Sometimes the "old" name is acceptable, in others not (Umtata for Mthatha). I find it very difficult to believe that not one of the cities that form up Ekurhuleni is on this list, Germiston alone has over 250 000 people. Perhaps specify that you are looking for traditional towns, not municipalities but that you are looking for the "new" name.
Thanks for the in-depth comment! I'm pretty sure that the source I'm using includes Ekurhuleni under Johannesburg's number. Also, I'll add a clarification to the caveats regarding what you said about the names.
According to the data from the website at the time, it fell short (the data for Namibia was from 2011 though). With newer data, if I update the quiz it should be there, along with Rundu